Metal primers and coating compositions modified with lower alkyl esters of unsaturated aliphatic acids



U i States a o 2,978,424 METAL PRIMERS AND COATING COMPOSITIONS MODIFIED WITH LOWER ALKYL ESTERS F UNSATURATED ALIPHATIC ACIDS Kenneth Atwood, Atlanta, Ga., and Austin K. Long, Bay Village, and Owen F. Shobe, Lakewood, Ohio, assignors to The Glidden Company, Cleveland, Ohio, a corporation of Ohio No Drawing. Filed Dec. 23, 1958, Ser. No. 818,702- 8 Claims. (Cl. 260-49) This invention relates to improved organic coating compositions such as metal primers, i.e. coating compositions whose protective qualitiesadapt them particularly for impeding and delaying the corrosion of corrosion-prone metals when applied directly to the surfaces of such metals. Ferrous metals are most often thought of in connection with metal primer coatings since, as is well known, ferrous metals are prone to develop rust and corrosion fairly rapidly when exposed to the atmosphere. The improved coatings of this invention are particularly useful on ferrous metals, and are especially useful as either initial primers on clean metal or as recoating primers wherethe ferrous metal surface which is to be primed has already become covered with rust. As is Well known, many fabricated ferrous metal structures such as bridges, storage tanks, oil refinery superstructures, ship superstructures, etc. are wholly and continuously exposed to the weather. Such structures have long been protected by painting and it has long been known that the protective paint must be renewed periodically. Such structures, when first erected are primed and top-coated. Such use of a metal primer is what is here termed an initial priming. As the initial protective coating system weathers away, some areas of the structure become inadequately protected and rust soon forms in such areas. Maintenance painting seeks to recoat the structures before this occurs, but many factors may interfere with Y the maintenance program to the end that the structure becomes rusted at least in some areas before the new maintenance coatings have been applied. Such maintenance coating systems usually involve the application of a metal primer as the initial coating. Such use of a metal primer is what we here term a recoating priming.

Initial and recoating primers are formulated to give the best possible protection against rusting of the underlying ferrous metal, and initial primers ordinarily do a better job than do recoating primers, mainly because the ferrous metal surface underlying the initial primer is fairly smooth and free of scaly rust. This latter type of rust is ordinarily encountered in the application of recoating primers and it has long been a recognized problem that even the best recoating primer and top-coat systems presently known ordinarily fail first in areas where such scaly, badly rusted areas are recoated. Sometimes determined efforts are made, as in the recoating of ships, to scrape off, sand blast, or otherwise remove as much of the rust as is practical, and especially to remove the scaly rust formations. Where this is done, the recoating protective primer/topcoat systems ordinarily give good protection against further rusting. The removal of all of the rust is, however, an expensive task especially in structures like bridges where much surface is exposed to the weather and where many lapped joints are involved. Consequently,

. the operation of removing all of the rust is frequently omitted and the structure is recoated without thorough surface preparation. Where such is the case, coating formulators seek to supply a primer/topcoat system which will still' offer goodtprotection, but at the'present time, as far as we are aware, the art recognizes that present primers with few exceptions are deficient in their ability to penetrate into and'throu'gh the loose rust so asto carry the corrosion-inhibiting pigments of the primers down 2,978,424 Patented Apr. 4, 1963.

to the plane of the interface between the clean metal and its overlying layer of rust.

We have now discovered that a restricted group of esters prepared from monohydric alcohols of upto 8 carbon atoms and monoca-rboxylic acids such as the fatty acids of dryingand semidrying oils or tall oil having a low (less than about 5% by Weight) rosin content are additives which confer to primers a greatly enhanced ability to wet and penetrate the rust on ferrous metal and similarly to wet and penetrate the corrosion found on other corroded metals. At least about five percent of the esters, by weight on the primers, appears to be necessary to this end with6-l0% preferred. Greater amounts can be used, however, especially where the acids of the esters are such that the esters possess oxidizing filmforming qualities of their own. Typical esters of the types mentioned above are methyl linoleate, butyl linoleate, butyl esters of tall oil, 2-ethyl hexyl esters of tall oil, methyl esters of linseed oil acids, ethyl esters of soybean oil acids, mixtures of the foregoing, etc.

Accordingly, it is an object of this invention to provide improved pigmented organic coating compositions characterized by having present in their formulations at least about five percent of said lower alcohol esters of the kinds mentioned above.

A further object is to provide improved coated metal articles protected with'coating systems employing coating compositions of the character set forth in the preceding object.

Still another object is to provide improved recoating primers for corroded metals, which primers exhibit improved wetting.

Another object is to provide improved recoating primers especially adapted for application to ferrous metal, at least some exposed surface portions of which are covered with rust.

These and other objects will be apparent from the following and preceding description of our invention.

It has long been recognized that most primers in common use have exhibited a tendency to merely cover the surface of a rusty area on ferrous metal without penetrating deeply thereinto. This lack of wetting and penetrating qualities leaves much porosity in the underlying lay ers of rust. The porosity entraps air and moisture, so that the rust-forming reactions can continue under the film. In time, the coating system overlying the rusty area becomes blistered and soon thereafter flakes off. We have now found that the ester additives referred to above,

when incorporated in the primer or like organic coating in EXAMPLE 1.METHYL LINOLEATE IN PRIMERS APPLIED TO CLEAN (NON-RUSTY) FERROUS METAL Tests for salt spray resistance, sea water immersion resistance and humidity were carried out on clean ferrous metal panels which had been coated with various primers containing or free of added methyl linoleate, and coating systems employing said primers plus top coats.

The following is a list of the primers employed. The

3 methyl linoleate used in some of the primers was a commercial product analyzing over 90% methyl linoleate, balance methyl esters of other octadecanoic acids.

Primer A.--Alkyd/lmseed zl/ red oxide chromated [)I1I77E1 Pigments:

Metallic brown 4 lb. Zinc chroinate lb. Chrome orange, rht, 0.1 lb. Zine oxide, lead-free- .75 lb. Magnesium silicate. .5 lb. Kieselguhr .25 lb. Silicapowder-.- .75 lb. Powdered litiinrgm... 10 lb. Fllin-lOllIlllliI solution and Raw linseed oil 2.375 pints. Alkyd resin solution 1 1.0 pint. Paint oil 1.25 pints Diacetonc alcohol. 50 pint. T.S. 28 solvcnt 1.625 pints Lead/mangau ese drier solution 3 liq. oz Lead drier solution 4 3 liq. oz Diammonium mono-hydrogen phosp a .e. 5 liq. oz Thickening agent (Bentone No. 38)"-.- 1.5 oz. av Phenolic resin/tong oil varnish solution 5 1.25 pints.

1 Glycerine, 64 1bs./phthalie anhyd, 100lbs., distilled linseed oil fatty acids, 1645 lbs. in mineral s irits, 253 gal; 63-65% solids by weight, acid number of 5-7, weighs 7.76 lbs/gallon.

2 Rosin, 75 lbs/litharge 2i lbs/tung oil, 150 gaL/minertil spirits 105 gaL/dipentene, 24 "a1.

3 Solution contai s 4.5% Pb derived from lead naphthenate (24% Pb) and 00% Mn derived from manganese naphtbcnate (6% Mn). Mineral spirits as solvent.

4 Mineral s' irits solution containing 6.05% Pl) derived from lead naphthcnatc (24% Ph).

5 Pre'iared from 200 lbs. commercial resin 1311-254 (100% oil-soluble paraphcnyl phenol/iormahlehyde resin of 100% solids); 26 gals. tune oil. Resin and oil cooked at 450 F. for 10-15 minutes, then cooled and reduced with 80 gals. xylol; varnish solution weighs 7.8 lbs/cal.

Nuact paste 44% Pb; 71% solids) .75 oz. (av.). Film-forming comprnents and modifiers:

Alkyd resin solution of Primer A-.- 3.25 pints. Methyl linolcate... 1.25 pints. T.S. '28 solvent 1 5 pints 40 Guiacol 0 5 liq. oz Phenolic resin v.11 n 1.5 pints T.S. 28 solvent 0 5 pint Cobalt drier solution 4 liq. oz Manganese drier solutici .375 liq. oz

.375liq. oz.

Lead drier solution B I A commercialprodu ct, said to be a lead organic compound functioning as drier/activator or drier absorption agent; contains 44% lead; solids content of 77%.

2 Contains 62-76% aromatics, has a liauri-butanol value of 08-74 and 02-7.]15 lbs/gal. at 60 F.; initial B.P.310 (min) to 300 F.

13.1 36i-379 1*. ed from 200 lbs. pure pheuol/i'ornialdehyde resin/E0 lbs. of 6% soluble allrylated phenol/formaldchyde resin/62 gals. Chinawood oil/6.75 fillS. of heat-bodied (visc. Z1-Zg) mixed linseed oil (44 lbs.)- China-wood o (6 lbs.l/10 pals, '1.S. 28 solvent/65 gals. mineral spirits. Weighs 7.65 1 1.; has solids content of 61%: acid number of 20-2]; and Gardner-H01 viscosity of K at 25 C.

4 IVlincral s irits solution containing 38-40% solids by weight of cobalt octoate containing 6% Co.

6 Mineral spirits solution containing 65% solids by weight of manganese naphthenate containinr 0% Mn. 5

6 The lead drier solution of Primer A.

Primer B.Ep0n ester primer, short oil type Pigments:

Red lead 05%.- Zinc chroniat Barytcs Magnesium s Bentone No. 38.. Lecithin Nunct paste (see Anti-skinning agent. Aluminum paste (65% solids 'al spirits)...

Film-forming components and modifiers:

Xylol solution of D00 acid ester of Epon 1004 resin (60% Emu/40% D00 acids) at solids by win; A.N. 7-10 (100% solids basis, viscosity (Garduer-Holdt) V-lV at 77 F.; 7.9 lb. (DUO-dehydrated castor oil).. Solvesso solvent No. 150 Isopropyl alcohol Cobalt octoate solution (38-40% solids by wt.

00 in octoate) .5 gal.

1 Epon 1004 is a bisphenol/epichlorhydrin polyether condensation product having terminal epoxy groups and reactive hydroxyl groups.

Primer B r Film-forming components and modifiers: Epon ester solution, supra Solvesso solvent No. 150.-- Isopropyl alcohol 36.4 gal.

24.0 gal.

4.0 gal.

Cobalt octoate solution.- .40 g Methyl linoleate 14.95 gal.

Primer C.Epon ester primer long ozl type Pigments:

Iron oxide pigment (88% FeZQ- 3 lb. Zinc ehromate 1.625 lb Zine oxide, lead-free. 875 lb. Silica powder 1.25 lb Asbestine .75 lb Film-forming components and modifiers:

Epon ester solution; 50% solids 7 pints.

Epon 100; resin.. 1,000 lb. Soy bean oil fatty ,210 lb T.S. 28 solvent (supra) 1,050 lb. Mineral spirits 1,050

First two materials reacted at about 500 F. under 00 until body of -F-G attained; then cooled and reduced.

Ethylene glycol monoethylether acetate 1 pint. Cobalt octoate solution (6% cobalt, supra) .25 liq. oz. Anti-skinning agent (containing wood phenols)- .25 liq. oz.

This primer can be reduced for spraying at rate of 4:1 with Xylol. It air dries overnight.

Primer C This primer duplicates Primer C except that the 8 pints of Epon ester solution and glycol ether acetate were reduced to 6.5 pints, and 1.5 pints of methyl linoleate was added. Thus the formulation in Primer C was: Film-forming components and modifiers- Epon ester solution, supra 5.07 pints. Ethylene glycol monoethylether ace .82 pint. Methyl linoleate 1.5 pints. Cobalt octoate solution, supra. .25 liq. oz. Anti-skinning agent, supra .25 liq. oz.

TOP COATS I. SELF CLEANING WHITE TANK PAINT Pigments:

'IiO rutile 1.625 lb. TiO anatase 1.75 lb Magnesium silicate (No. 390 SF). .875 lb Modified bentonite (Bentone No. 38) .03 lb Nuact paste, supra .0 17 lb Film-forming component and modifiers:

Linseed oil modified glyccryl phthalate alkyd 1 pint (847 lbs. oil/100 lbs. glycerinc/2l0 lbs. phthalic anhydi, 8.3 lbs/gal; 100% solids; AN. 9-12;

T-U visc. Gardner-Holdt). Soya oil (60%) Ipentaerythritol (13.7%) lphthalic 2.875 pints.

anbydride (26.3%), alkyd resin varnish reduced to 60% solids in mineral spirits (7.85 lbs/gal). Hi Flash coal tar naphtha 1.0 pint.

Grind all above and then add:

Soya oil 0%)/pentaerythritol (13.7%)lphtbalic 2.5 pints.

anhydride (26.3% wt.) alkyd resin reduced in xylol to 70% solids.

Hi Flash coal tar naphtha .625 pint.

Zinc naphthcnate (8% zinc) .125 oz.

Lead/manganese naphthenate (24% P .125 oz in mineral spirits at 20% solids.

Lead naphthenate (24%Pb) in mineral spirits at .125 oz.

14% solids.

Guaiacol .016 oz.

Norm-Reduce 10:1 with xylol for spraying; air dries in 24 hours.

1.1. ALKYD/VINYL Coronrmna REsiN WHITE TANK PAINT Fatty acid (34% wt.)/ethy1ene glycol (9.6%)/phthallc 1.19 pints.

anhydride (37.5%)/pentacrythritol (18.6%) alkyd resin reduced in xylol to 60% solids content; 8.4 lbs./gal A.N. 5-6.

phthalie anhydride/p-tert. butyl benzoic acid alkyd at 60% solids in xylol; A.N. 10; 44.5% oil acids; 29.5% phthalic anhyd./5.0% benzoic acid/ 70% excess polyol; 8.2 lbJgal; vise. C-D Gar ner-I-Ioldt) Xylol. Lecithin Dimcthyl silicone anti silking flui N OTEr-ThlS tank paint weighs 10.2 lbs/gal; 54% solids; visc. 70-80 at F. (No. 4 Ford cup); air dries over night; reduce 16:1 with toluo for spraying.

.mmi

Primer A ompletely blistered. Primer A. Excellent. Primer B.. Excellent. Primer B Excellent. Primer C Blistered. Primer C.. Excellent.

430 HOURS. IMMERSION IN SEA WATER Top-coated systems using:

Primer A Failed by blistering in 120 hrs. Primer A' Excellent after 430 hrs. Primer B Badly blistered. Primer B. Excellent. Primer C Failed by blistering after 340 hrs. Primer C Blistering after 430 hrs. Panels coated with:

Primer C only-.- Completely blistered. Primer C only Slightly blisterad at end of 430 hrs.

1080 HOURS IMMERSION IN SEA WATER Primer Top- Primer Coated 1 Only A. 0 A 7 6 B. 7 0 B 8 10 C- 0 0 C 8 SALT SPRAY TESTS 350 830 Hours Hours- Primer Top- Coated 1 Top- Primer Coated Only SALT SPRAY 575 HOURS Plain, Clean Steel Pre-Rusted Steel Primer Top- Primer Top- Primer Coated 1 Only Coated l 1 Primed with indicated primer, dried, then top-coated.

SEA WATER IMMERSION 575 HOURS Plain, Clean Steel Pre-Rusted Steel Primer Top Primer Top- Primer Coated Only Coated 1 HUMIDITY 250i HOURS; V'IOFCOATED 1 Primer Plain Pre- Steel Rusted A- 0 0 A 6 8 B. 6 8 B 6 8 Primed with indicated primer, dried and then top-coated.

EXAMPLE 2 Primers A and A were used as controls in the 01- 6 lowing tests of coated steel panels wherein three analogous primers A2, A3 and A4v were used differing only in that the methyl linoleate of Primer A' was replaced with an equal weight of the wetting'additive identified below: I

SALT SPRAY 980 HOURS Primer Wetting Additive 'Iop Primer Coated Only N one 0 0 Methyl linoleate 5 5 Butyl esters of linseed oil acids 3 3 Buty esters of'unsaturated fatty C18 4 4 aei s. A4 Butyl esters of tall 011 (about 2% rosin 5 5 content by weight).

Sea Water-1,000 Hours Humidity- Hours Top- Prlmer Top- Primer Coated 1 Coated 1 Only 1 Same meaning as in Example 1.

EXAMPLE 3 To illustrate the universality of the invention, a Federal Specification paint IT-P-86A was tested along with three' modifications of it. A first modification, here identified as TT-P-86A modified, involved the formulation shown below. The second and third modifications consisted of removing the phenolic resin/tung oil solids to an extent of 6% of the total paint solids and adding methyl linoleate to a level of 6% by weight on the coating in TT-P-86A and in TT-P-86A modified. The resulting four coatings were applied as primers, dried and then were top coated partially. The top coat was a commercial tank intermediate paint whose formulation is given below. The coated panels were dried and some of them were then exposed outdoors for four months and others were exposed in a conventional Weatherometer test cabinet for 350 hours (which period of time is roughly equivalent to a year of outdoor exposure). The exposed panels were then scraped with a knife to see how poorly or how firmly the coatings adhered to the panel. The panels having no methyl linoleate in their primers were easily flaked oil by scraping, both coatings coming oil? in wide strips and exposing'the metal underneath. In contrast, the comparative test panels having methyl linoleate in their primers were diflicult to penetrate by scraping, and demonstrate that the coating composition has penetrateddeeply into the rusted surface and has securely bound the rust to the metal surface.

Amiueral spirits solution of 259' solids h wei ht; contains 0.25 On; 1.42% Pb; 0.97% Mn by wei ht. 7 y g PANEL LABELLED 1+6% WA" The above formulation was modified by withholding 26% of the raw linseed oil and 26% of the bodied linseed oil, and by replacing the withheld oils with an equal volume of methyl linoleate.

PANEL LABELLED '2 L101). TT-P BGA.

PANEL LABELLED 2+6% WA Above formulation modified by replacing 26% of the raw linseed oil with methyl linoleate.

TANK INTERMEDIATE PAINT Magnesium s. Powd. litharge Film-formers and mo Alkyd resin prepared from soybean oil (2944 lbs.)/pen- 33.75 gal.

taerythritol (672 lbs.)/phthalic anhyd. (1200 lbs.)/ powdered litharge (1.75 lbs.) and reduced in mineral spirits to 60% solids. 'I.S. 28 solvent (supra) .75 gal. Mineral spirits. 10.00 gal. Enamel vehicle pure phenol-formalde- 14.5 gal.

hyde resin (200 lbs.)/100% oil-soluble alkylated phenol/ formaldehyde resin (footnote 3, Primer) supra (50 lbs.)/tung oil (62 gals.)/T.S. 28 solvent (10 gals.)/hcat bodied mixture of linseed oil (88%)ltung oil (12%) of Z Z; viscosity (6 75 gals.)/mineral spirits (65 gals.). Raw linseed oil 9.625 gal. Mineral spirits .5 gal. Mixed lead nap Pb)/manganese naph- 1.25 gal.

thennte (6% him/mineral spirits drier solution supra. Zinc naphthenate solution (8% zinc) (65% solids) 1.875 gal. Guaiacol .125 gal. Dipheuyl Mercury dodecenyl succinate; 22% solids; .75 gal.

EXAMPLE 4 This example has reference to a group of panels which have been tested for fracture resistance of the applied coatings. The panels were all of iron which had been pro-rusted and which then had been primed with Primer A of Example 1 modified in the manner shown in Primer A to contain 0, 3, 5, 6, and 10% of methyl linoleate by weight on the total paint solids. The upper of each primed panel was then coated with the White intermediate tank paint of Example 3. When this coat was dry, the upper two-thirds of each panel was coated with a grey commercial tank top-coat whose formulation is set forth below. All the panels were then conditioned for testing by exposing in the weatherometer for 350 hours, and then were bent about a conical mandrel and examined for fractures in the coatings. It became evident that -6% of methyl linoleate was conducive to minimum fracturing.

GREY TOP COAT TANK PAINT T102 rutile 202 lb Magnesium silicate No 39 85 lb. Yellow oxide of 1ron.... 5 lb. Antimony black No. 1.. 16 lb. Bentonc No. 38 supra 2.51b. Nuact paste supra .0 lb. Hi Flash coal tar naphth 10.625 lb Soybean oil, pentaorytlir alic litharge /mineral spirits solution, of tank intermediate paint, supra 30.511). Linsced/glycerine/phthalic/litharge varnish of Primer A.- 10.62511).

Grind above, then add: Soybean oil (2,944 lbs.) /pentaerythritol (672 lbs.)/phthalic 26.6 gal.

anliydride (1260 lbs.) lpowd. litharge (1.75 lbs.)/xylo1 (2000 lbs), alkyd resin solution. Hi Flash coal tar naphtha 6.625 gal. Mixed lead/manganese drier solution oi tank intermediate 1.3 gal.

paint. Leadnaphthenate drier (24% Pb) in mineral spirits at 14% 1.3 gal.

solids. V Zintlrrltaphthenate drier (8% Zn) at 65% solids 1.3 gal.

so 1 s. Super Ad it supra .3 gal. Guaiacol .16 gal forming or binding materials which can be used in our coating compositions.

(1) Any of the many known oleoresinous varnishes 8 prepared from (a) drying and/or semi-drying oils in their various bodied and unbodied, modified and unmodified forms with (b) conventional varnish resins in conventional proportions of oil(s) to resin(s).

(2) Alkyd resins modified with triglyceride 0i1(s) and/ or varnish resins, with the modifiers in proportions corresponding to the range covered by long to short oil length.

(3) Phenolic/aldehyde condensation products reacted with or otherwise modified with triglyceride (usually drying and semi-drying) oils and/or varnish resins, to give air-drying varnish-type materials.

(4) Varnishes which are a blend of alkyd resins (2 above) and the modified phenolic condensation products (3 above), with or without added triglyceride drying and/or semi-drying oils.

(5) Epoxy esters, i.e. epoxy resins of the bisphenol/epichlorhydrin type which have been reacted with rosin acids, resin acids, and/or saturated and unsaturated fatty acids of drying and semi-drying oils, thereby to yield substantially full esters having substantially zero epoxy and/or hydroxy equivalent but being air drying by reason of ethylenic unsaturation in the esters.

(6) Triglyceride-oil-base binders with or without modifying proportions of alkyd resins blended therewith.

(7) In some special instances, vinyl/ alkyd blends can be used, e.g. copolymers of vinyl chloride and vinyl acetate blended with alkyd resins which have been modified with drying and/or semi-drying oils. These blends are preferably top-coats, however.

Coating compositions utilizing binders such as those listed above can be pigmented with anticorrosive pigments such as the following:

Red lead Blue lead Lead chromate Zinc dust/zinc oxide Zinc chromate Basic lead silico chromate Calcium chromate Barium chromate Calcium plumbate Strontium chromate Iron oxide(s) Zinc tetroxy chromate Conventional color pigments and/or fillers (inerts) can be included if desired to yield pigment volumes between about 25-60%.

While the resulting coatings are preferably applied to metal as initial or recoating primers, they can be employed as temporary top-coats because of their moderate weatherability.

In coating systems employing our compositions as either initial or recoating primers, then the dry prime coat can be top-coated with any known air-drying paints of established weatherability. The film-forming materials listed above for our compositions find use also in topcoats but are then pigmented mainly for color and durability rather than for anticorrosive qualities.

Following is a typical formulation of coating compositions utilizing the present inventions.

TYPICAL FORMULATION Example formulations within the "Typical Formulation" are as follows.

Soya oil (60%)lpentraerythritol (13.7%)/phthalic anhydride (26.3%) alkyd resin varnish reduced to 60% solids in mineral spirits (7.85 lbs/gal.)

9 A mixture of methyl linoleate and air-drying oil-modified phenolic] aldehyde condensation product, in the proportions of 52 gallons of methyl linoleate to 48 gallons of said air-drying ondensation product.

3 The varnish described in note 3 or rlmcr A Quick'aryingred lead primer for priming bridges, fall/CS j W and structural steel I i This is a fast drying red lead primer with goodchemical resistance and excellent resistance to blisteringirom exposure to high humidity and moisture The phenolic resin penetrating liquid is included to give better wetting Composition Percent Weight Volume Pigment:

Red lead (97% Grade) 88.00 1, 391. 18.900

Asbestine (Nyta1300 or equal). 7. 91 125.00 5. 265

Celite 2. 26 35. 70 2. 127

Aluminum stearate 42 6. 70 800 Litharge (powdered)... 1.13 17. 85 223 N uact paste (supra) 28 4. 46 319 Vehicle:

Alkyd varnish TT-R-266, Type II,

Class A 1 33.00 183.0 23. 43 Phenolic resin penetrating liquid 37. 54 208. 0 27. 89 Tom; oil 4. 73 26. 2 3. 35 Aromatic mineral spirits 13.30 74. 8 10. 03 Cellosolve (ethyleneglycol monoethyl ether) 9. 35 51. 8 6. 68 Guaiacol 45 2. 279 Lead naphthenate (24% Pb) supra 1. 21 6. 7 698 Manganese naphthenate (6% Mn) supra 42 2. 2 279 1 Alkyd varnish ofTypical formulation" supra. Z Penetrating liquid of "typical formulation" supra. Pigment 68% Vehicle... 32% WtJgal- 21.33 lbs P.V 40.5% Non volatile by volume.. 8% Non volatile by weight 89.4% Viscosity. 85-90 K.U Grind. 5-6. Theoretical coverag 816 sq it./gal. at 1.5 mils dry. Dry to recoat 24 hours. Reduce to spray- 8-1 with VM & P naphtha. Brush Full body.

GRAY-GREEN FINISH COAT Composition Percent Pounds Gallons Pigment:

Basic lead silico chromate 77.00 391. 5 11.4 Rutile titanium dioxide (nonchalking) 14. 25 72. 4 2. 6 Carbon black 38 1.936 1 Phthalocyanine blue 75 3. 87 3 0.1 chromium ox1de.. 6.10 31.0 6 Bentone 38 76 3. 87 3 Nuact paste 76 3.87 3

Vehicle:

Alkyd varnish 1 61. 0 393. 0 50. 2 Phenolic resin Penetrating liquid 16. 5 106. 14. 2 Phenolic varnish a 7. 52 48. 6 6. 2 Aromatic mineral spirits (320390 F. 7 4 48.0 6.4 Diacetone alcohol 6.05 39. 2 5.1 Lead naphthenate (24% Pb) 72 4. 64 5 Manganese naphthenate (6% Mn)- 1. 30 2 Zinc naphthenate (8% Zn) 16 1.045 1. 3 Guaiacol anti-skin agent 45 2. 92 3 1 Alkyd varnish of typica formulation, supra. 2 Penetrating liquid of typical formulation, supra. 8 Phenolic varnish of typical formulation," supra.

8 to 1 VM & P to spray. Brush Full Body.

1Q From the foregoing description of ou r invention it will be clear that the principles thereof can be embodied in a variety of specificallydiii erent formulations in which our identified lower alcohol esters of monocarboxylic.

sufiicient to bring the pigment volume into the range of I about 25% to 60% of the total volume of said coating composition, and a liquid wetting additive in an amount corresponding to about 5-10% by weight of said coating composition, said wetting additive being at least one ester of (A) monohydric alcohol selected from the group consisting of aliphatic and cycloaliphatic monohydric alcohols having up to eight carbon atoms, and (B) monocarboxylic acids selected from the group consisting of (a) the fatty acids of triglyceride drying and semi-drying oils, and (b) mixtures of said fatty acids with small amounts of rosin acids.

2. A coating composition as claimed in claim 1 where in the Weather resistant film-forming material is selected from the group consisting of air-drying oleoresinous varnishes, air-drying alkyd resins containing modifiers in an amount corresponding to the range covered by long to short oil length, air-drying oil-modified type of phenolic/aldehyde condensation product, mixtures of said alkyd resins and phenolic/aldehyde condensation products, mixtures of said alkyd resins with said phenolic/aldehyde condensation products and triglyceride drying and semi-drying oils, air-drying monocarboxylic acid esters of bisphenol/epichlorohydrin epoxy resins, said epoxy esters having substantially zero epoxy and hydroxy equivalents, triglyceride oils of the drying and semi-drying classes, mixtures of said triglyceride oils with said alkyd resins, and mixtures of vinyl chloride/vinyl acetate copolymers With oil-modified air-drying alkyd resins.

3. A coating composition as claimed in claim 2 wherein said wetting additive is present in an amount between about 6% and 10% by weight of said coating composition.

4. A coating composition as claimed in claim 3 wherein anticorrosive pigment is present in amounts between about 18-77% of the total pigment.

5. A coating composition as claimed in claim 4 Wherein the wetting additive is methyl linoleate.

6. A coating composition as claimed in claim 5 Wherein the Wetting additive is a mixture of methyl linoleate and air-drying oil modified phenolic/aldehyde condensation product, in the proportions corresponding to 52 gallons of methyl linoleate to 48 gallons of said air-drying condensation product.

7. A wettingadditive adapted for use in protective coating compositions for metal, said additive being a blend of methyl linoleate and air-drying oil-modified phenolic/ aldehyde condensation product in which said materials are present in the proportions of about 52 gallons of methyl linoleate to 48 gallons of said air-drying condensation product.

8. A pigmented coating composition consisting essen tially of: an organic-solvent solution of film-forming Weather resistant material of the air-drying type, dispersed pigment, and a liquid wetting additive in an amount corresponding to about 5-10% by weight of said coating composition, said wetting additive being at least one ester of (A) monohydric alcohol selected from the group con sisting of aliphatic and cycloaliphatic monohydric alcohols having up to eight carbon atoms, and (B) monocarboxylic acids selected from the group consisting of (a) the fatty acids of triglyceride drying and semi-drying 12 Dec. 30, 1941 11 oils, and (b) mixtures of said fatty acids with small amounts of rosin acids.

References Cited in the file of this patent UNITED STATES PATENTS FOREIGN PATENTS 472,249 Great Britain Sept. 15, 1937 543,427 Canada July 9, 1957 Cushman Mar. 28, 1911 Taylor Jan. 5, 1926 Griesinger Jan. 9, 1940 

1. A COATING COMPOSITION ADAPTED FOR USE AS A PROTECTIVE COATING IN DIRECT CONTACT WITH CORRODED METAL SUCH AS RUSTY FERROUS METAL, SAID COMPOSITION CONSISTING ESSENTIALLY OF: AN ORGANIC-SOLVENT SOLUTION OF FILM-FORMING WEATHER-RESISTANT MATERIAL OF THE AIR-DRYING TYPE, DISPERSED PIGMENT INCLUDING ANTICORROSIVE PIGMENT IN AN AMOUNT SUFFICIENT TO BRING THE PIGMENT VOLUME INTO THE RANGE OF ABOUT 25% TO 60% OF THE TOTAL VOLUME OF SAID COATING COMPOSITION, AND A LIQUID WETTING ADDITIVE IN AN AMOUNT CORRESPONDING TO ABOUT 5-10% BY WEIGHT OF SAID COATING COMPOSITION, SAID WETTING ADDITIVE BEING AT LEAST ONE ESTER OF (A) MONOHYDRIC ALCOHOL SELECTED FROM THE GROUP CONSISTING OF ALIPHATIC AND CYCLOALIPHATIC MONOHYDRIC ALCOHOLS HAVING UP TO EIGHT CARBON ATOMS, AND (B) MONOCARBOXYLIC ACIDS SELECTED FROM THE GROUP CONSISTING OF (A) THE FATTY ACIDS OF TRIGLYCERIDE DRYING AND SEMI-DRYING OILS, AND (B) MIXTURES OF SAID FATTY ACIDS WITH SMALL AMOUNTS OF ROSIN ACIDS. 